The objective of the proposed research is to develop ultrasensitive chemiluminescent assays for HIV-1 antibodies by Western blotting and immunoblotting assays for cystic fibrosis. The applicant has developed a proprietary dual-enzyme- label chemiluminescent detection system combining the actions of alkaline phosphatase (AP) and horse radish peroxidase (HRP). AP hydrolyzes a substrate to produce a luminescence enhancer for generating chemiluminescence from a new proprietary substrate for HRP. The applicant will label each member of a pair of probes with AP or HRP. Binding of both probes by an analyte on a membrane, as in Western and immunoblotting assays, places the enzymes in close proximity, facilitating chemiluminescence enhancement. In addition, the applicant will develop sets of chemiluminescent reagents for these assays. The proposed research should provide a new generation of chemiluminescent tests with improved sensitivity and specificity over colorimetric and other chemiluminescent tests. Technology developed will be applicable to research kits for performing chemiluminescent assays for proteins and nucleic acids.